We have seen some supposed 'fat-finger' trades in the last few days but Stockholm's stock exchange was brought to its knees yesterday as a record-breaking order hit the book and halted trading for four hours. A 4.3 billion contract buy order in the OMX30 futures (the Swedish equivalent of the Dow futures) caused the fiasco. This is equivalent to a SEK460 trillion notional exposure - or 131 times the Swedish GDP (around USD70 trillion). As one trader of the exchange noted, via SvD Narangsliv, "This just shows that it can get really bananas with machines" referring to the growing element of automated securities trading on that exchange. What's Swedish for FUBAR?

The giant warrant december semester in OMXS30, a security equivalent to a basket consisting of the Stockholm Stock Exchange's 30 largest companies, and where trade is very important for the overall pricing of the stock market.

The order was on buy side of the order book and covered more than 4.2 billion futures, to a unit price of almost 107,000 dollars. It gives a theoretical value of 459 561 500 030 000, ie nearly 460 trillion dollars. Sweden's gross domestic product, by comparison, amounted in 2011 to more than 3500 billion.

- This just shows that it can go really bananas with machines, writes a trade to Svenska Dagbladet, referring to the growing element of automated securities trading.

According to the Exchange spokesman Carl Norell has no order of that size team into the system. Instead, it is about a parsing incurred in exchange system due to a technical error. The order, Norell writes in an email, anullerades, but still remains a problem why the index derivatives market is closed since just before 10 am this morning.